#include<stdio.h>
#include<stdlib.h>
int main()
{
    int a,b;
    int x=10;
    int y=10;
    int height = 20;
    int v1=1;
    while(1)
    {
        x=x+v1;
        system("cls");
        for(a=1;a<=x;a++)
            printf("\n");
        for(b=1;b<=y;b++)
            printf(" ");
        printf("o");
        printf("\n");
        if(x==height)
            v1=-v1;
        if(x==0)
            v1=-v1;
    }

    return 0;
}
